© 2011 MLB Advanced Media, L.P. All rights reserved.

02/28/11 4:56 PM ET

Nats hop on Mets' pitching in Harper's debut

PORT ST. LUCIE, Fla. -- Angel Pagan celebrated his position change with a solo homer Monday afternoon, but the Nationals beat the Mets, 9-3, in Bryce Harper's Nats debut at Digital Domain Park.

After Matt Stairs drove in the game's go-ahead run with a single in the fifth, Harper pinch-ran for Stairs to make his official debut. The top pick in last June's First-Year Player Draft, Harper later struck out in both his at-bats.

"I knew what was coming. I pulled my front side a little bit in both at-bats," Harper said. "The first at-bat, I saw three sliders, but I felt really good. It's the first two at-bats in Spring Training. And I have a long way to go."

Hours after the Mets named him their starting center fielder over Carlos Beltran, Pagan lost Ian Desmond's first-inning fly ball in the sun and misplayed it into a triple, ultimately resulting in the game's first run. But Pagan hit an opposite-field solo home run off Nationals starter Chad Gaudin in the bottom of the inning to tie the game at 1.

"I'm glad it happened," Pagan said of the misplay. "You're going to have some of those, too, in New York -- there's a tough sun in New York. You want to work on that."

Gaudin and Mets starter Mike Pelfrey pitched three innings apiece in their Grapefruit League debuts, each allowing two runs on five hits.

Mets reliever D.J. Carrasco ceded single runs to the Nationals in the fourth and fifth innings to take the loss. Craig Stammen pitched two innings of one-run relief to record the victory.

Mike Morse sealed the game for the Nationals with a two-run homer off Taylor Tankersley in the seventh.

Up next: Francisco Rodriguez will make his Grapefruit League debut -- not to mention his first game appearance since last August -- when the Mets travel to Viera, Fla., on Tuesday for a 1:05 p.m. ET rematch against the Nationals. Rodriguez missed the final month of last season after tearing a right thumb ligament in an off-field altercation. Also scheduled to appear for the Mets are three players fighting for roster spots: second basemen Brad Emaus and Justin Turner, and reliever Pedro Beato.

Nationals manager Jim Riggleman announced that Harper will appear in a second straight game against the Mets on Tuesday at Space Coast Stadium. Harper will be a defensive replacement for right fielder Jayson Werth, who will make his Nationals debut.

Anthony DiComo is a reporter for MLB.com. Follow him on Twitter @AnthonyDicomo. This story was not subject to the approval of Major League Baseball or its clubs.